CLC vs LC has benefits I never knew before

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Nick
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#16 Re: CLC vs LC has benefits I never knew before

Post by Nick »

This is all the result of trying to explain thing using language that is not suited to what you are trying to explain (as I tried to explain elsewhere).
I suppose the difference between regulated and none regulated supply is the operation point, which is held constant with regulation
Not really, remember that above a certain frequency the cap at the end of the power supply is working to decouple the supply and will function to (within limits) fix the voltage at that point. The fact that you can measure with a meter that the addition of the load changes the voltage from the power supply is just because you are measuring the DC voltage at that point, and there is no cap big enough to sustain the voltage at DC. All the regulator is doing (if it helps you to picture it) is behaving like a infinitely large decoupling cap, and no one has considered getting worried about that cap altering the operating point because the voltage across it does or doesn't change.
modulated by the signal 'on top ' of the operation voltage.
I think its this "on top" thing that is the cause of your confusion there is just the way it is now at this instant, and then there is the way it is at the next now an instant later, and so on, and also as I said at Owston, you cant just think in terms of voltage you also have to think in terms of current AT THE SAME TIME. I think its the "same time" part that trying to think about it with words where the problem comes as the words allows an abstraction from reality that means that the link between the description and the reality is meaningless.
its just in my mind a totally fixed operating point that includes the signal, is not how a valve was designed to operate... or is it
A valve was not designed to operate, a valve was invented and then we found how it operated, you have causality the wrong way there. Remember the most important thing A valve is only aware of the voltages and currents on its pins it knows of nothing else. This is also true of every other electronic component. If you understand that and what it means it will all make sense. If you don't it never will.
ps. there's quite a lot of difference between series-reg and shunt-reg in terms of what happens in the PS, to achieve that aim.
Though in the context of this attempt at an explanation that difference is of zero importance, the power supply can be considered as a perfect voltage source in series with a resistor and a cap after that resistor. All that varies (that matters to this discussion) if you use or don't use a regulator is the size of the resistor.
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#17 Re: CLC vs LC has benefits I never knew before

Post by steve s »

You are correct about my use of the correct language Nick,

And i think I agree with what you've said above.

And your right the valve only sees what voltage is on its pins at a precise moment.
But that was also my point too.

But that's also the part I'm struggling to get my brain to understand.

I know my terminology is suspect..
But to simplfy, if the regulated supply includes the signal in the reference voltage, and a standard supply doesn't, is there a difference to the operating point (whilst playing music
which I assumed understanding of) different between them

your answer is no...? Why would there be ?
And I'm still struggling to understand why wouldn't be a difference.
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#18 Re: CLC vs LC has benefits I never knew before

Post by Nick »

If the voltage on the B+ line (for want of giving it a name) varies with the current the valve pulls, then to the valve it looks like there is a larger resistance on its anode. The fact that that resistance is the anode load (in the case of supply with a low impedance because of either a regulated supply or a cap that is able to supply the demanded current with minimal change in voltage) or the anode load in series with the impedance of the supply only matters to the valve in that the voltage on its pins will differ for a given current in the two cases.

So yes, what I think you mean by the operating point will change. In both cases, by slightly different amounts.

But what I don't understand is why you seem to feel that that current and voltage relationship with a regulated supply would be worst in some way than without a regulated supply.

It may be confusing matters, but the operating point we think of when we look at a set of anode curves, is itself a simplification, it should really be a surface, but as its on paper the lines attempt to display the 3D surface as a set of 2D curves. In operation the valve conditions exist as a point that moves over that surface.
But to simplfy, if the regulated supply includes the signal in the reference voltage, and a standard supply doesn't, is there a difference to the operating point ?
Part of my confusion is I don't know what "includes the signal in the reference voltage" means.
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#19 Re: CLC vs LC has benefits I never knew before

Post by IslandPink »

Sorry, crossed with Nick here, but maybe this is still helpful :
steve s wrote: Thu May 19, 2022 3:52 pm I know my terminology is suspect..
But to simplfy, if the regulated supply includes the signal in the reference voltage, and a standard supply doesn't, is there a difference to the operating point (whilst playing music
which I assumed understanding of) different between them
Would it help to clarify this bit ?
In the case of a series-reg supply , there is a reference voltage provided either by a VR tube, or Zener(s). This is a reference , it's not affected by ( or including ) the music signal.
OK so under signal conditions, varying current demand on the B+ line will tend to raise or lower the B+. The regulation action takes place by taking a pick-off the B+ line, this goes back into the reg circuit , where typically a pentode ( acting as a voltage amplifier ), using the voltage reference to set its operating points, applies a correcting signal into a bank of 6080's ( or similar ) which raise or lower the current going into the B+ line, so correcting the B+ voltage back to the nominal set value.
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#20 Re: CLC vs LC has benefits I never knew before

Post by steve s »

IslandPink wrote: Thu May 19, 2022 4:10 pm Sorry, crossed with Nick here, but maybe this is still helpful :
steve s wrote: Thu May 19, 2022 3:52 pm I know my terminology is suspect..
But to simplfy, if the regulated supply includes the signal in the reference voltage, and a standard supply doesn't, is there a difference to the operating point (whilst playing music
which I assumed understanding of) different between them
Would it help to clarify this bit ?
In the case of a series-reg supply , there is a reference voltage provided either by a VR tube, or Zener(s). This is a reference , it's not affected by ( or including ) the music signal.
OK so under signal conditions, varying current demand on the B+ line will tend to raise or lower the B+. The regulation action takes place by taking a pick-off the B+ line, this goes back into the reg circuit , where typically a pentode ( acting as a voltage amplifier ), using the voltage reference to set its operating points, applies a correcting signal into a bank of 6080's ( or similar ) which raise or lower the current going into the B+ line, so correcting the B+ voltage back to the nominal set value.
Thanks Mark, but at the risk of me looking even thicker..
If the regulator is not seeing the music signal how is the modulation on the powersupply suppressed, that appears at odds to my understanding or may be you are describing different types of regulation
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#21 Re: CLC vs LC has benefits I never knew before

Post by Nick »

Would it help to clarify this bit
No because IMHO it would make it less clear, that is what happens, but it doesn't matter in any real terms WRT operating points. Yes, you can hear the regulator, that's why I use a CR filter to isolate it from the load, and yes, in practice the regulator does look a lot more complex (and yes that is meant to be a pun) than a simple resistor. And if that's what Steve is talking about then ok, but its not in any way clear to me if it is (or isn't).

But there is just as much interaction between the load and the load and the supply and the supply to the supply and the primary of the transformer, all the way back to the power station furnace, in the case of a unregulated supply. Its not a case of "simple and pure" vs "complex", its just different versions of complex.

Now I guess I could be less vague, but that would involve lying about how it actually works.
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#22 Re: CLC vs LC has benefits I never knew before

Post by steve s »

Nick wrote: Thu May 19, 2022 4:07 pm

So yes, what I think you mean by the operating point will change. In both cases, by slightly different amounts.


Thanks nick. We have got there .. and that was my only point...
And I'll apologise for all the confusion caused.
To add, that change is totally signal related, and the amount of change in the real life 'dynamic ?' operating point of any valve I would guess is dependant on the signal.
Like so many other aspects of amplifier operation, the music signals affect is where the trouble starts?
Last edited by steve s on Thu May 19, 2022 4:35 pm, edited 1 time in total.
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#23 Re: CLC vs LC has benefits I never knew before

Post by Cressy Snr »

My take is that, yes, you do want the power supply to modulate, but you want the DC the modulation rides on to be, as far as possible, a fixed entity. If it isn’t then the music signal will not be a bigger copy of what went in, so you need regulated DC or an infinitely large cap, for the music to remain unmolested. It’s the least worst option when compared to the others.
Last edited by Cressy Snr on Thu May 19, 2022 4:37 pm, edited 1 time in total.
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#24 Re: CLC vs LC has benefits I never knew before

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Nick wrote: Thu May 19, 2022 4:25 pm
Would it help to clarify this bit
No because IMHO it would make it less clear, that is what happens, but it doesn't matter in any real terms WRT operating points. Yes, you can hear the regulator, that's why I use a CR filter to isolate it from the load, and yes, in practice the regulator does look a lot more complex (and yes that is meant to be a pun) than a simple resistor. And if that's what Steve is talking about then ok, but its not in any way clear to me if it is (or isn't).

But there is just as much interaction between the load and the load and the supply and the supply to the supply and the primary of the transformer, all the way back to the power station furnace, in the case of a unregulated supply. Its not a case of "simple and pure" vs "complex", its just different versions of complex.

Now I guess I could be less vague, but that would involve lying about how it actually works.
Thats had me laughing.. thanks...
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#25 Re: CLC vs LC has benefits I never knew before

Post by Nick »

If the regulator is not seeing the music signal
The regulator is seeing the music signal in that the load presented to the regulator is at any time the current demanded by the load, and that current is varying because of the music signal. But what I am saying is that as long as the voltage remains constant as that current varies, it doesn't matter that the regulator sees the load. As long as the load see's a constant voltage independent of the current its wanting to pull, it doesn't care if that constant voltage is created by huge caps, a battery or a regulator. That side of the line is where the dragons live, so don't look over that side.

As I say again, if that's what you mean then fine, yes all that goes on, but the non regulator case is far far worst, but somehow that is being perceived as "better". And in both cases, the solution can be as simple as a cap to decouple one side from the other.

the major case where a shunt and a series reg will differ is if you try push current back into the regulator, the shunt is fine with that but the series hates it, but that's adding complexity and only in practice matters with inductive loads
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#26 Re: CLC vs LC has benefits I never knew before

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My take is that, yes, you do want the power supply to modulate
No, you don't want the power supply to modulate, you want to modulate a copy of the power supply which is your output signal. What you don't want is the copy process to alter the original. As you say, if the copy changes the original you are into face to face mirrors and infinite regress.
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#27 Re: CLC vs LC has benefits I never knew before

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steve s wrote: Thu May 19, 2022 4:19 pm Thanks Mark, but at the risk of me looking even thicker..
If the regulator is not seeing the music signal how is the modulation on the powersupply suppressed, that appears at odds to my understanding or may be you are describing different types of regulation
The regulator ( as a whole ) is seeing the effect on B+ caused by the music signal.

The voltage reference is not affected, it just works with the pentode and the set-up around that, to provide you with a given B+ value which you typically set using a pot, witht the amp circuit drawing its nominal standing current.
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#28 Re: CLC vs LC has benefits I never knew before

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Nick wrote: Thu May 19, 2022 4:38 pm

but the non regulator case is far far worst, but somehow that is being perceived as "better". And in both cases, the solution can be as simple as a cap to decouple one side from the other.
I'm on the fence...
I've always perceived a (very slight) change in dynamics with what I've heard from regulated supplies, a small price to pay for the advantages it brings. My understanding could explain that. ? Or not !

Not that any one understands what I say anyhow, as this afternoon has proved !
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#29 Re: CLC vs LC has benefits I never knew before

Post by ed »

I'm going to offer something, but if it clouds the issue or I am wrong, then please tell me to shut up!!!

I'm reading this and thinking why was signal mentioned in the discussion in the first place....
surely the point is that the valve is drawing different current at different times(no need to mention why at this stage) and when it draws a relative larger current the ps tries to deliver this....if the ps struggles to deliver this current it momentarily sags and the whole dynamic changes ever so slightly....

if the ps is stable enough not to sag under changing conditions then there is no change in the dynamics, or the op point if you will.

so we want a ps that is stable under changing current requirments...is this where the regulator comes in?

now I considered the mention of signal to be superfluous to the discussion when it seems so much easier to discuss the current instead...
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#30 Re: CLC vs LC has benefits I never knew before

Post by steve s »

IslandPink wrote: Thu May 19, 2022 4:48 pm
steve s wrote: Thu May 19, 2022 4:19 pm Thanks Mark, but at the risk of me looking even thicker..
If the regulator is not seeing the music signal how is the modulation on the powersupply suppressed, that appears at odds to my understanding or may be you are describing different types of regulation
The regulator ( as a whole ) is seeing the effect on B+ caused by the music signal.

The voltage reference is not affected, it just works with the pentode and the set-up around that, to provide you with a given B+ value which you typically set using a pot, witht the amp circuit drawing its nominal standing current.
Thanks Mark, yet another example of my poor terminology
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